NewZed

If you measured 9 volts on one of the wires that is about right (actually it's low but it should still run your pump), with the voltage drop from the starter. You tested the pump and it works. That leaves the ground. Edit 2 - rethinking the 9 volts. That's pretty low even with the starter draw. Seems like the battery needs charging before further testing. It's not really clear why you were measuring continuity when all you needed was voltage and ground. If you disconnect the yellow wire at the starter solenoid you can get power to the pump without the engine turning over. The fuel pump will get power at Start but the starter won't. Makes it easier for testing. You can hear the fuel pump.

Here is a picture I took a while ago that might help you figure out where your problem is. It's the distance from the clutch fork to the head of one of the slave cylinder mounting bolts, on a properly working clutch system. It should tell you if you have the correct TOB sleeve inside. A short sleeve will measure more than 6 cm, a too-tall one will measure less. This is the starting point, and travel is fine.

Looks like Nissan used the R180 with the automatic transmission. 3N71B.

You're almost there. Your test of touching the wires together, which created a spark from the MSD box, shows that the last, missing, piece is the trigger from the pickup coil. You showed that you have a good pickup coil. The trigger voltage from the magnetic pickup is caused by a ferrous piece of metal passing by, the six bladed metal wheel next to the pickup coil. If you have a sensitive meter, or an analog meter, or an oscilloscope, you can see the voltage from the pickup coil when the distributor spins. Nissan even drew a picture of what the voltage looks like on an oscilloscope in the FSM, Engine Electrical chapter. Find a way to see if you're getting that voltage pulse when the engine spins. You haven't confirmed that the distributor shaft spins with the engine, for example. Things slip or break or get put together wrong. People have had the drive gear slip on the shaft. People forget to put the rotor under the cap. If you're testing for spark at the coil main wire take the distributor cap and rotor off and spin the distributor by hand. Or just watch it when you turn the engine over. Or lift the distributor up and spin it by hand with the key on. Lots of possibilities. Focus on the triggering system. One thing that might cause problems is if you have the wires connected backward. Maybe switch the red for the green. Usually it just causes timing problems but maybe the MSD is more sensitive and won't work with a backward waveform. There's also an air gap adjustment that needs to be right to generate voltage. Check that.

The test that you did here shows that your MSD wiring was correct. You're just not getting the voltage pulse from your distributor. Your MSD wiring looks right, it's your distributor's magnetic pickup signal that is not getting through. When you touch the green and violet wires together you create a voltage pulse that mimics what the distributor should do. Focus on the distributor.

And make sure the distributor is actually turning when the engine turns. You're at the "don't assume anything" point.

Measure resistance across the wires from the magnetic pickup in the distributor, with them disconnected. You might have the wrong ones connected or have a bad pickup. Should be about 720 ohms. You won't get repeated spark unless the trigger is triggering.

And, of course, there's always the possibility that you have a bad pickup coil in the distributor. Confirm proper resistance and air gap. But, you have two in there so you can always use the other.

Make sure that you're not losing power to your toggle switch when you turn the key to Start. The ignition system turns off all accessory power during Start to give maximum current to the coil. Start and Run are two different circuits.

There should be some troubleshooting steps here - https://static.summitracing.com/global/images/instructions/msd-6425.pdf

No, you want to connect the BW and BL wires from your ignition switch directly and together to the thin red wire. They provide the power to the MSD box with the key on and during Start. Power from the thick red wire passes through the box to the coil positive. The thin red wire turns the box on. If you're using a relay or switch for the thin red wire power, instead of the ignition switch, and it stays on while you're trying to to Start, then their might be something wrong with the box. It should spark if the thin red wire has power and all of the other wires are connected as shown.

I mis-wrote in my other post. MSD runs all power through the MSD box. There's an ignition wire, red, and a "heavy" power wire, also red. You only show one red wire, not real clear which one. By your drawing, you're missing one red wire. The BW and BL wires should both be connected to the thin red ignition wire, "original coil + wire". Yours would be the "magnetic pickup" scheme.

It's an old car that looks cool. Some people buy them just to have them in the garage, and never actually drive them. If you're looking for a daily driver, read through the many threads on this site to see what's involved in keeping them running. Looks like you should plan on having two cars for a while. Ideally, the other will be a truck so that you can haul parts, like engines and transmission. And expect to spend some money. Nickels and dimes will add up quickly. If it didn't need time and money he probably wouldn't be selling it. Lastly - do you like your neighbor now? Because you're going to find all of the "previous owner" stuff he did. Or he might be hanging out all the time pining over his old car.

Make sure that the original module is disconnected. And think of the MSD box as the make/break circuit on the grounded side, the negative side, of the coil. The coil gets power, the MSD box lets current flow, the MSD box cuts the current when the trigger wires tell it to...spark happens. Break it down in to the basics.

L = Blue

MSD has a wiring diagram and instructions. Probably better to use that. The first diagnostic test is to measure coil voltage with the key On and at Start. No power, no spark. Coil power doesn't come through the MSD box. There are two power wires for 1976.

I think that that type of thought process is what started his problem.

Odd, somebody must have started from basics but overlooked the old system. And never finished the job. Beware, there's a problem with the 280Z's that drains the battery after the Atlanticz method. The brake warning lamp check relay stays on after the swap. 1976 for sure, not sure about 75 and 77. There's another wiring scheme out there but it leaves the Charge light off. There are a few threads around the internet about it. Good luck.

Here's some good stuff. Diagrams are farther down and S and L are ID'ed. The alts are all similar. http://www.atlanticz.ca/zclub/techtips/alternatorswap/index.html

He said he doesn't have a charge light. You do. So it can't be exactly the same. Dig in to S and L and forget about wire colors. Use a meter.

What year 280Z? And do you know if the alternator is internally regulated (it probably is but you never know)? Internally regulated alternators are actually super simple to wire up. S connects to battery/charge wires. L connects to the light in the voltmeter. Sounds like the PO got his S and L backward and rigged some things up to try to make sense of what was happening. Some of the alternators actually have S and L molded into the alternator case. I'd start over and focus on those two wires. The light nthe meter is not an LED. It's just a bulb behind a red lens.

You seem to have too many "lights". A bulb and an LED. Where did this wiring scheme come from, it's odd? Sounds like the "S" wire is not connected. It Senses charge voltage and the regulator uses it to regulate voltage. Your "bulb" must be connected to the L circuit. When it's disconnected the windings lose power and charging stops. Not clear why the gauge has a red LED. Is it the stock gauge or some aftermarket gauge? Is this a new problem or has the wiring scheme never worked? You have some wrongness going on.

No. ZX's don't have mustache bars. The R180 mustache bar is different from the R200 mustache bar. It's possible to stretch and oblongate and torque and pry a variety of parts in. Get the parts and start installing. That's what most do. There's always some part you'll have missed or some modification you'll need to do. Good luck. Don't forget the speedo gear.

You'll need an R200 mustache bar and cross brace to replace your R180. The T5 needs some custom work as Sleeper noted. The propeller shaft from the ZX won't swap over and your 240Z one won't work, you'll need a custom length. The T5 doesn't really offer much more than a stock 5 speed. "T5" is a name for hundreds of different types of Borg Warner transmissions. It doesn't mean super-strong. The T5 swap is where the fabrication and cost is. Find a 71B 5 speed and the swap will be bolt on/straight swap parts, no fab required. Many people use the 71B behind the turbo engines.